#600 - Specialized support function for Ball1 and Ballp

[schillic]

See #600.

The default implementation needs to allocate the support vector, which can be avoided.

julia> B1 = rand(Ball1, dim=100); d = rand(100);

julia> @time ρ_old(d, B1)
  0.000010 seconds (2 allocations: 912 bytes)
8.280132936590725

julia> @time ρ_new(d, B1)
  0.000013 seconds (1 allocation: 16 bytes)
8.280132936590725

###

julia> Bp = rand(Ballp, dim=100); d = rand(100);

julia> @time ρ_old(d, Bp)
  0.000023 seconds (3 allocations: 1.766 KiB)
11.071392754318621

julia> @time ρ_new(d, Bp)
  0.000016 seconds (1 allocation: 16 bytes)
11.071392754318621